Capsule endoscope

ABSTRACT

An embodiment comprises and apparatus having an image capture device with an image axis and a gyroscope operable to indicate the orientation of the image axis. An embodiment of a capsule endoscopy system comprises an imaging capsule and an external unit. The imaging capsule may comprise an image capture device having an image axis and a gyroscope operable to indicate the orientation of the image axis. The external unit may comprise a gyroscope operable to indicate an orientation of a subject and a harness wearable by a subject and operable to align the gyroscope with the subject. The imaging capsule may send and image to an external unit for processing and display, and the external unit may provide for calculation of the image-axis orientation relative to the body.

PRIORITY CLAIM

The instant application claims priority to Chinese Patent ApplicationNo. 201010603106.2, filed Dec. 17, 2010, which application isincorporated herein by reference in its entirety.

SUMMARY

An embodiment of an image capture device comprises an image axis and agyroscope operable to indicate the orientation of the image axis.

An embodiment of a capsule endoscopy system comprises an imaging capsuleand an external unit. The imaging capsule may include an image capturedevice having an image axis and a gyroscope operable to indicate theorientation of the image axis. The external unit may include a gyroscopeoperable to indicate an orientation of a subject and a harness wearableby the subject, and is operable to align the gyroscope with an axis ofthe subject. The imaging capsule may send an image to the external unitfor processing and display, and the external unit may calculate theimage-axis orientation relative to the body.

For example, in such an embodiment, the imaging capsule may be ingestedand images of a subject's gastrointestinal system, and the external unitmay determine the orientation of the imaging capsule's image axisrelative to the subject's body.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is presented by way of at least one non-limitingexemplary embodiment, illustrated in the accompanying drawings in whichlike references denote similar elements, and in which:

FIG. 1 is a cross-sectional view of a human subject and of an embodimentof a capsule endoscopy system that includes an imaging capsule and anexternal unit.

FIGS. 2 and 3 are side views of the human subject of FIG. 1 in standingand supine positions, respectively.

FIG. 4 is a block diagram of an embodiment of the imaging capsule ofFIG. 1.

FIG. 5 is a block diagram of an embodiment of the external unit of FIG.1 operatively connected with a computer.

FIG. 6 is diagram of the human subject of FIGS. 1-3 and of a coordinatesystem for the subject's frame of reference.

FIG. 7 is a diagram of the imaging capsule of FIGS. 1 and 4 and ofcoordinate system for the capsule's frame of reference.

FIG. 8 is a diagram of a coordinate system for a frame of referencewithin which the human subject of FIG. 6 and the imaging capsule of FIG.7 may be located.

DETAILED DESCRIPTION

Endoscopy, or internal examination of a living subject such as a human,may be performed with an endoscope that is inserted into a body opening(e.g., mouth or anus) and that allows a physician to internally view abody cavity (e.g., esophagus, stomach, colon, or intestine) that isaccessible via the opening. Examination of the gastrointestinal tract(“GI tract”), for example, includes inserting the endoscope into themouth, down the esophagus, and into the stomach and/or intestines.Similarly, examination of the colon (e.g., a colonoscopy), for example,includes inserting the endoscope through the anus into the colon.

Unfortunately, such a procedure may be invasive and uncomfortable for asubject, and may necessitate general anesthesia. Moreover, such aprocedure may require sterile endoscopy equipment and a sterileenvironment. Accordingly, an endoscopy procedure is generally performedin a hospital setting, which may increase the cost of such a procedure.

FIG. 1 is a cross-sectional view of a human subject 100 and anembodiment of a capsule endoscopy system 105 that includes an imagingcapsule 110 and an external unit 115. As discussed in further detailherein, the imaging capsule 110 may be swallowed, and thereafter maypass through the esophagus 120, through the stomach 125, through theintestines 130 (the esophagus, stomach, and intestines may becollectively referred to as the GI tract 140), and out the anus 135 asdepicted in FIG. 1. As it makes its journey through the subject's GItract 140, the imaging capsule 110 may be operable to capture images ofthe GI tract 140 along an imaging axis 145 and to transmit the capturedimages to the external unit 115. The imaging capsule 110 may berecovered when it leaves the body of the subject 100, or may be disposedas part of the subject's waste (e.g., via a toilet during a bowelmovement).

Compared to conventional endoscopy as discussed above, the endoscopysystem 105 described herein is non-invasive because a subject 100 needonly swallow the imaging capsule 110 and wear the external unit 115 asthe imaging capsule travels through his/her GI tract 140. Therefore, noanesthesia is believed to be required in most cases, and imaging via theendoscopy system 105 need not be performed in a sterile hospitalsetting, or even at a doctor's office. In fact, once the subject 100swallows the imaging capsule 110, the subject may move about normally asthe imaging capsule captures images of the subject's GI tract 140. Thismay significantly reduce the cost of endoscopy procedures and maysignificantly reduce the discomfort and inconvenience of the subject100.

The imaging capsule 110 may assume numerous orientations relative to thesubject 100 while traveling through the GI tract 140, such that theimage axis 145 may be pointing in any direction at any given time.Therefore, images captured by the imaging capsule 110 may be taken fromnumerous orientations within the GI tract. As described further herein,because a physician may want to know the relative orientation of eachimage relative to the GI tract 140 for purposes of analysis anddiagnosis, the external unit 115 and imaging capsule 110 may be operableto indicate, for each image, the orientation of the imaging capsule 110relative to a frame of reference of the subject 100. For example, forimages of the subject's stomach, a doctor may wish to know if the imageis of, e.g., the back of the stomach, the front of the stomach, the topof the stomach, or the bottom of the stomach.

FIGS. 2 and 3 are side views of the human subject 100 respectivelystanding and lying down, with an embodiment of the imaging capsule 110inside the subject 100 and an embodiment of an external unit 115 beingworn by the subject 100.

The external unit 115 is coupled to the subject 100 with a harness 210,which may be a belt or strap of a suitable material that encircles thesubject 100 and maintains an axis 245 of the frame of reference of theexternal unit 115 in alignment with an axis 250 of the subject's frameof reference regardless of how the subject 100 may move. That is, theharness 210 maintains the unit's axis 245 approximately parallel to orapproximately co-linear with the subject axis 250. For example, thesubject 100 in FIG. 2 is shown standing with the body axis 250 alignedwith a gravity vector {right arrow over (G)}, and the subject in FIG. 3is laying down with the body axis 250 perpendicular to the gravityvector {right arrow over (G)}. In both subject orientations, the harness210 maintains the external-unit axis 245 in approximate alignment withthe body axis 250.

Additionally, FIGS. 2 and 3 depict the imaging capsule 110 in twodifferent orientations relative to the frame of reference of the subject100. Although both FIGS. 2 and 3 depict the image axis 145 of thecapsule 110 oriented in the same direction relative to the earth's frameof reference, i.e., aligned with the gravity vector {right arrow over(G)}, the orientation of the image axis relative to the frame ofreference of the subject 100, and thus relative to the body axis 250, isdifferent. FIG. 2 depicts the image axis 145 pointing toward the distalinferior extremities of the subject 100 (e.g. down toward the legs,etc.) in parallel with the body axis 250. However, FIG. 3 depicts theimage axis 145 pointing toward the posterior of the subject 100,perpendicular to the body axis 250. As discussed herein, the orientationof the image axis 145 relative to the body axis 250, and thus to thesubject's frame of reference, 100 may be determined based on orientationindications provided by the imaging capsule 110 and the external unit115. The orientation of images captured by the imaging capsule 110 maythereby be determined relative to the body axis 250 as further discussedherein so that a physician, such as a radiologist, may determine theorientation of each image relative to the subject's GI tract. That is,an image's orientation may be toward the front of the subject, towardthe back of the subject, etc. Knowing an image's orientation relative tothe subject may facilitate the physician's analysis of the image, andmay facilitate the physician formulating a diagnosis of the subject.

FIG. 4 is a block diagram of an embodiment of the imaging capsule 110 ofFIGS. 1-3. The imaging capsule 110 includes a housing or capsule shell405, and disposed within the housing is an imaging-module integratedcircuit (IC) 410, which may be formed from one or moreintegrated-circuit dies. For example, the imaging-module IC 410 may be asystem on a chip.

The imaging module chip 410 includes a processor 420, a gyroscope 430, awireless transceiver module 440, a light source 450, a power source 460,a lens assembly 470, and a pixel array 480. The focal axis of the lensassembly 470 and the array axis normal to the center of the pixel array480 are approximately aligned along the image axis 145. That is, thepixel array 480 is operable to capture an image of an object towardwhich the image axis 145 points.

The shell 405 may be formed of any suitable material, and may be anysuitable size and shape. For example, in an embodiment, the shell 405may be operable to be ingested and to pass through the gastrointestinaltract of the subject 100 (FIGS. 1-3). Therefore, the shell 405 may be ofa size (e.g., pill or medicinal-capsule size) suitable for ingestion bythe subject 100, and may be formed from a material that is resilient tothe conditions experienced within the gastrointestinal tract of thesubject such that the imaging capsule may remain functional for itsentire journey through the subject's GI tract 140. Additionally, atleast the portion of the shell 405 through which the image axis 145extends may be transparent so that images may be captured through theshell. For example, if the pixel array 480 is sensitive toelectromagnetic energy having wavelengths in the visible portion of theelectromagnetic spectrum, then this portion of the shell 405 may betransparent to these visible wavelengths. Likewise, if the pixel array480 is sensitive to electromagnetic energy having wavelengths in theinfrared portion of the electromagnetic spectrum, then this portion ofthe shell 405 may be transparent to these infrared wavelengths.Additionally, the shell 405 and other components of the imaging capsule110 may be made of environmentally friendly material so that if theimaging capsule is intended to be disposable (i.e., not recovered whenleaving the subject 100), the imaging capsule would have little or nonegative environmental impact as waste.

The imaging-module IC 410 may be an integrated circuit, a hybridintegrated circuit, a micro-electro-mechanical system (MEMS), or anysuitable system. Furthermore, as discussed above, the components of theimaging-module IC 410 may be disposed on a single IC die or on multipleIC dies. Additionally, the imaging-module IC 410 may include more orfewer components than are described herein, and such components may beconfigured in any suitable arrangement.

The processor 420 may be any suitable processor, processing system,controller, or module, and may be programmable to control one or more ofthe other components of the imaging capsule 110. Furthermore, theprocessor 420 may perform image processing on images captured by thepixel array 480 before the images are transmitted to the external unit115 (FIG. 1-3).

The gyroscope 430 may be any suitable device operable to indicate adegree of rotation about one or more coordinate axes of the gyroscope'sframe of reference. For example, the gyroscope 430 may be operable todetect “yaw”, “pitch”, and “roll” (i.e., rotation) about coordinate X,Y, and Z axes, respectively. Examples of gyroscopes suitable for thegyroscope 430 include the STMicroelectronics L3G4200DH and the L3G4200D.In an embodiment, there may be a plurality of gyroscopes 430.

The wireless module 440 may be any suitable device that is operable tosend and receive wireless communications. For example, the wirelessmodule 440 may be operable to send to the external unit 115 (FIGS. 1-3 &5) images captured by the pixel array 480 and indications of rotationfrom the gyroscope 430; the external unit may use these indications ofrotation to calculate the orientation of the image axis 145 for eachreceived image. Furthermore, the wireless module 440 may allow one tocontrol the operation of one or more components of the imaging capsule110, and may allow one to program the processor 420. Moreover, thewireless module 440 may send status information to the external unit115, such as the level of power remaining in the power source 460, orthe intensity of the illumination provided by the light source 460 (theimaging capsule 110 may include a sensor, not shown in FIG. 4, tomeasure the intensity of the light source).

The light source 450 may be any suitable device (e.g., one or morelight-emitting diodes) operable to provide illumination to aid incapturing images. For example, the light source may be operable toprovide sufficient illumination while in the gastrointestinal tract ofthe subject 100 such that the pixel array 480 may capture an image. Thelight source 450 may provide continuous illumination, or may provideflash illumination as is suitable for the application, for example,under the control of the processor 420. Additionally, the intensity ofillumination may be modified, e.g., by the processor 420 (the lightsource 450, or the image capsule 110, may include an intensity sensor(not shown in FIG. 4) that is coupled to the processor). Alternatively,the light source 450 may be omitted, for example, if the pixel array 480is sensitive to infrared wavelengths. In an embodiment, there may be aplurality of light sources 450.

The power source 460 may be any suitable source of power such as abattery, and may provide power to one or more components of the imagingcapsule 110. The power source 460 may be recharged via a wiredtechnique, or may be recharged wirelessly (e.g., via RF energy). In anembodiment, there may be a plurality of power sources 460.

The lens assembly 470 may be operable to focus, or otherwise to modifyelectromagnetic energy (e.g., visible light) such that the energy may besensed by the pixel array 480 to capture an image. Collectively, thelens assembly 470 and pixel array 480 may constitute an image-captureapparatus, and may be arranged as a single imaging module, assembly, orunit. As discussed above, the normal to the center of the pixel array480 and the focal axis of the lens assembly 470 are approximatelyaligned along the image axis 145, which “points” in the direction of anobject (or portion of an object) whose image the pixel array maycapture. The lens assembly 470 may be any suitable type of imaging lensassembly, such as a macro lens, process lens, fisheye lens, orstereoscopic lens.

In an embodiment, the pixel array 480 and lens assembly 470 may beoperable to capture images in various regions of the electromagneticspectrum, including infrared, ultraviolet, or within visible light. Inan embodiment, the pixel array 480, lens assembly 470, or both the pixelarray and the lens assembly, may be separate from the imaging modulechip 410. Additionally, in an embodiment, the lens assembly 470 may beomitted. In an embodiment, there may be a plurality of pixel arrays 480lens assemblies 470.

FIG. 5 is a block diagram of an embodiment of an external system 500,which includes an embodiment of the external unit 115 and an embodimentof an optional computer 510 coupled to the external unit. The externalunit 115 includes a processor 520, a gyroscope 530, a wireless module550, and a power source 560.

The processor 520 may be any suitable processor, processing system,controller, or module, and may be programmable to control one or more ofthe other components of the imaging capsule 110. Furthermore, theprocessor 520 may perform image processing on images captured by thepixel array 480.

The gyroscope 530 may be any suitable device operable to indicate adegree of rotation about one or more coordinate axes of the gyroscope'sframe of reference. For example, the gyroscope 530 may be operable todetect “yaw”, “pitch”, and “roll” (i.e., rotation) about coordinate X,Y, and Z axes, respectively.

The wireless module 540 may be operable to send and receive wirelesscommunications. For example, the wireless module 540 may be operable toreceive from the imaging capsule 110 (FIGS. 1-4) images captured by thepixel array 480 and indications of rotation from the gyroscope 430. Thewireless module 540 may also be operable to wirelessly communicate withthe computer 510. The wireless module 540 may be any suitable devicethat is operable to send and receive wireless communications.Furthermore, the wireless module 540 may allow one to control theoperation of one or more components of the external unit 115, and mayallow one to program the processor 520 via, e.g., the computer 510.Moreover, the wireless module 540 may send status information to thecomputer 510, such as the level of power remaining in the power source560. Furthermore, the wireless module 540 may act as a “go-between” forthe capsule 110 (FIG. 4) and another device such as the computer 510.

The computer 510 may be any suitable computing device (e.g., a laptop ordesktop computer) that is directly or wirelessly coupled with theexternal unit 510, and may be operable to program the external unit 115,obtain stored data from the external unit 115, process data obtainedfrom the external unit 115, and the like. The computer 510 may also beoperable to program the processor 420 of the imaging capsule 110 (FIG.4) either directly or via the external unit 115. Furthermore, thecomputer 510 may be operable to process image data received from theimaging capsule 110 directly or via the external unit 115, and torecover one or more images from this data, to determine the orientationof the image axis 145 (FIG. 4) for each recovered image as discussedbelow in conjunction with FIGS. 6-8, and to display each recoveredimage. The computer 510 may also be able to send the recovered imagesand other related information to a remote location, such as a doctors'office, via the internet. Accordingly, the subject 100 (FIGS. 1-3 and 6)may be able to go about his/her normal activities such as working orsleeping as the imaging capsule 110 travels through the subject's GItract 130 (FIG. 1), and images captured by the imaging capsule could besent in real time to the doctor's office over the Internet. The powersource 560 may be any suitable source of power such as a battery, andmay provide power to one or more components of the external unit 115.The power source 560 may be recharged via conventional wired methods, ormay be recharged wirelessly (e.g., via RF energy). In an embodiment,there may be a plurality of power sources 560.

In an embodiment, the endoscopy system 105 described herein may also beused to capture images within a non-human subject 100. Additionally, theendoscopy system 105 or components thereof may be used to capture imageswithin non-living systems, such as systems of pipes, a moving body ofwater, or the like.

FIG. 6 is a coordinate system 600 of a frame of reference of the subject100, the coordinate system having the axes X_(BODY), Y_(BODY), andZ_(BODY), interposed on the subject, wherein the Z_(BODY) axis isaligned with the body axis 250 of the subject. Given that the spine 605of the subject 100 is not typically linear within the coronal plane ofthe subject, the Z_(BODY) and the body axis 250 may be aligned with ahypothetically straightened spine, or may only be aligned with the spinealong the sagittal plane. As the subject 100 changes position theX_(BODY), Y_(BODY), and Z_(BODY) remain stationary relative to thesubject. In other words, the X_(BODY), Y_(BODY), and Z_(BODY) are fixedrelative to the subject's 100 frame of reference. For example, if thesubject 100 lies down, then the Z_(BODY) axis will maintain the samealignment with the body axis 250.

As depicted in FIG. 6, the X_(BODY) axis extends along the mid-sagittalplane of the subject 100 perpendicular to the frontal plane of thesubject, and the Y_(BODY) axis is perpendicular to the mid-sagittalplane of the subject or co-linear with and along the frontal plane ofthe subject. The Z_(BODY) axis extends in alignment with the body axis(i.e., parallel to the body axis 250 superiorly from the axis origin).

In an embodiment, the external unit axis 245 (FIGS. 2 and 3) (i.e., theorientation of the external unit 115) is assumed to represent the bodyframe of reference 600. Because external unit 115 may be worn on theoutside of the subject 100, the body frame of reference 600 and theexternal unit axis 245 may not be directly aligned. Therefore, anassumption may be made that the external unit axis 245 is aligned withthe body axis 250, and that the external unit 115 frame of reference isthe same as the subject 100 frame of reference 600. Accordingly, theexternal unit 115 worn by the subject 100 may be assumed to be detectingchanges in the orientation of the body axis 250 within the subject frameof reference.

Although the X_(BODY), Y_(BODY), and Z_(BODY) are depicted as havingspecific orientations relative to the body of the subject 100, inanother embodiment, the X_(BODY), Y_(BODY), and Z_(BODY) axes may havedifferent orientations relative to the subject, and need not be alignedwith a plane, the spine 605, or other part of the body. Therefore, thealignments of the X_(BODY), Y_(BODY), and Z_(BODY axes) shown in FIG. 6merely represent one possible configuration of the axes. Additionally,the X_(BODY)Y_(BODY) plane may be moved up and down relative to theZ_(BODY) axis.

FIG. 7 is a coordinate system 700 frame of reference for the capsule 110having the axes X_(CAP), Y_(CAP), and Z_(CAP), interposed on the imagingcapsule, wherein the Z_(CAP) axis is aligned (i.e., parallel to orco-linear) with the image axis 145 of the imaging capsule. As theimaging capsule 110 changes position, the X_(BODY), Y_(BODY), andZ_(BODY) axes remain stationary relative to the imaging capsule. Inother words, the X_(CAP), Y_(CAP), and Z_(CAP) are fixed relative to theimaging capsule's frame of reference. Additionally, as discussed abovein conjunction with FIG. 6, the alignment of X_(CAP), Y_(CAP), andZ_(CAP) may be in any desired orientation; for example, the Z_(CAP) axisneed not be aligned with the imaging axis 145, although such alignmentmay make easier the calculations for determining the orientation of theimaging axis 145 relative to the subject's frame of reference 600.

FIG. 8 is a terrestrial coordinate system 800 having the axes X_(EARTH),Y_(EARTH), and Z_(EARTH), wherein the Z_(EARTH) axis is aligned withvector {right arrow over (G)}, which represents the direction of thegravitational force of the earth. Depicted within the coordinate system800 are a body orientation Z^(N) _(BODY), and a cap orientation Z^(N)_(CAP). The terrestrial coordinate system 800 is fixed to the earth'sframe of reference. Additionally, the body orientation Z^(N) _(BODY),and the cap orientation Z^(N) _(CAP) respectively represent theorientation of the subject's 100 frame of reference and the imagingcapsule's 110 frame of reference at a given time N relative to theorigin of terrestrial coordinate system 800.

The Z^(N) _(BODY) orientation represents an orientation of the Z_(BODY)axis (FIG. 6) relative to the terrestrial coordinate system 800 at agiven time N, e.g., Z¹ _(BODY), Z² _(BODY), Z³ _(BODY), etc. Forexample, as the subject 100 changes position (e.g., lies down, bendsover, reclines, etc.) the orientation of the Z_(BODY) axis of thesubject 100 would change relative to the terrestrial coordinate system800.

The Z^(N) _(CAP) orientation represents an orientation of the Z_(CAP)axis (FIG. 7) relative to the terrestrial coordinate system 800 at agiven time N (e.g., Z¹ _(CAP), Z² _(CAP), Z³ _(CAP), etc.). For example,as the imaging capsule 110 changes orientation within the GI tract 140of the subject 100 (as the image capsule moves through thegastrointestinal tract) the orientation of the Z_(CAP) axis may changerelative to the terrestrial coordinate system 800. Additionally, theorientation of the Z_(CAP) axis may change relative to the Z_(BODY)axis, and vice versa.

Z^(N) _(CAP) and Z^(N) _(BODY) may be defined within the terrestrialcoordinate system 800 by spherical coordinates relative to the earthX_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system 800. For example, θ_(BODY)and φ_(BODY), are depicted in FIG. 8 as spherical coordinates of Z^(N)_(BODY), where θ_(BODY) represents an angle from the positive Y_(EARTH)axis projected in the X_(EARTH)Y_(EARTH) plane (e.g., in radians from 0to 2π) with the vertex being the origin, and where φ_(BODY) representsan angle from the positive Z_(BODY) axis (e.g., in radians from 0 to π)with the vertex being the origin. Accordingly, θ_(BODY) and φ_(BODY),for example, define the orientation Z^(N) _(BODY) from the origin of theX_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system 800. Similarly, θ_(CAP)and φ_(CAP) (not shown in FIG. 8), define the orientation Z^(N) _(CAP)from the origin of X_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system 800.

As Z^(N) _(CAP) changes direction relative to the terrestrial coordinatesystem 800 as the imaging capsule 110 moves through the gastrointestinaltract capturing images, knowing the orientation of Z^(N) _(CAP) relativeto Z^(N) _(BODY) may be important when interpreting the images capturedby the image capsule 110. For example, for a given image or a series ofimages, it may be important to determine whether the image axis 145 ispointing toward the back, legs, head, or front of the subject 100 sothat the images may be properly interpreted or so that images may becombined.

Given that the Z^(N) _(CAP) and Z^(N) _(BODY) orientations may be bothcontinuously and independently changing relative to each other overtime, the orientation of Z^(N) _(CAP) relative to the body coordinatesystem 600 may be calculated by synchronizing or calibrating the frameof reference of the external unit 115 and the frame of reference of theimaging capsule 110 (FIGS. 1-5) relative to each other, relative to theterrestrial coordinate system 800, at Z⁰ _(CAP) and Z⁰ _(BODY) and thentracking the orientations of the imaging capsule 110 and external unit115 (which is assumed to represent the body frame of reference) overtime as images are captured by the imaging capsule 110. As depicted inFIG. 9, the frame of reference of the external unit 115 can be assumedto have the same origin as X_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system800. Also, the frame of reference of the imaging capsule 110 may not bealigned with the frame of reference of the external unit 115; however,the frame of reference of the imaging capsule 110 may also be assumed tohave the same origin as the X_(EARTH)Y_(EARTH)Z_(EARTH) coordinatesystem 800 as depicted in FIGS. 10 and 11. Therefore, the external unit115 frame of reference and imaging capsule 110 frame of reference can betranslated into the X_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system 800 sothat the orientations Z^(N) _(CAP) and Z^(N) _(BODY) are within a commonframe of reference and these orientations may be assumed to be relativeto the origin of the X_(EARTH)Y_(EARTH)Z_(EARTH) coordinate system 800,regardless of the position of the external unit 115 (i.e., the subject100) or imaging capsule 110, relative to each other.

For example, a doctor may initially synchronize or calibrate theexternal unit 115 and imaging capsule 110 by having the subject 100stand while wearing the external unit coincident to or parallel with thegravitational force of earth {right arrow over (G)} and Z_(BODY), whilethe doctor holds the imaging capsule parallel with the gravitationalforce of earth (e.g., away from the ground), as depicted in FIG. 9. Theexternal unit 115 and imaging capsule 110 may be calibrated orsynchronized, e.g., by pressing a button on the external unit, or viathe computer 510 (FIG. 5). The orientations of the external unit 115 andimaging capsule 110 may thereafter be tracked in relation to each otherover time as the subject 100 swallows the imaging capsule and as theimaging capsule travels through the subject's GI tract 140.

For example, presuming that the external unit 115 and imaging capsule110 are initially synchronized or calibrated having the orientationsdepicted in FIG. 9 (i.e., Z⁰ _(CAP)=(0,0) and Z⁰ _(BODY)=(0,0)), theexternal unit 115 and imaging capsule 110 will be assumed to both changeorientation relative to the earth coordinate system 800 from theserespective initial orientations. Any change in orientations of theexternal unit 115 and imaging capsule 110 may be tracked relative tothese initial orientations based on changes in orientation detected bythe respective gyroscopes 430, 530 (FIGS. 4 and 5). Roll, pitch and yawφ, θ, ψ indicated by the gyroscopes 430, 530 may be converted intospherical coordinates or other desirable orientation indications byknown methods. (Note the lower-case symbols φ, θ, ψ of roll, pitch andyaw as opposed to the upper-case symbols θ and φ, in sphericalcoordinates).

Accordingly, as the subject 100 and external unit 115 changeorientation, and as the imaging capsule 110 changes orientation withinthe subject 100 while capturing images, the orientation of the imageaxis 145 may be determined relative to the subject coordinate system 600(FIG. 6) but independent of the orientation of the external unit 115(i.e., the subject 100) within the terrestrial frame of reference 800.

For example, assume that the external unit 115 and imaging capsule 110are initially synchronized or calibrated having the initial orientationsdepicted in FIG. 9, (i.e., Z⁰ _(CAP)=(0,0) and Z⁰ _(BODY)=(0,0)). Thenassume that the subject 100 and imaging capsule assume the orientationsdepicted in FIG. 10, wherein the subject reclines such that Z¹_(BODY)=(90°, 180°) and that Z¹ _(CAP)=(45°, 135°). Further assume thatthe capsule gyroscope 430 reports a roll, pitch and yaw of R¹(−45°, 45°,−90°)_(CAP) and that body gyroscope 530 reports a roll, pitch and yaw ofR¹(−90°, 0°, −90°)_(BODY).

To determine the normalized rotation (R^(N) _(NORMAL)) and normalizedorientation (O^(N) _(NORMAL)) of the image axis 145 (i.e., theorientation of the image axis relative to the body coordinate system 600frame of reference), one may use the following equation: R¹ (φ, θ,ψ)_(CAP)−R¹(φ, θ, ψ)_(BODY)=R¹(φ, θ, ψ)_(NORMAL). (i.e.,R¹φ_(CAP)−R¹φ_(BODY)=R¹φ_(NORMAL); R¹θ_(CAP)−R¹θ_(BODY)=R¹θ_(NORMAL);R¹ψ_(CAP)−R¹ψ_(BODY)=R¹ψ_(NORMAL)). Returning to the example above, (φ,θ, ψ)_(NORMAL) may be calculated as follows: R¹(−45°, 45°,−90°)_(CAP)−R¹(−90°, 0.0°, −90°)_(BODY)=R¹(45°, 45°, −0°)_(NORMAL). Asdepicted in FIG. 11, this corresponds to a normalized orientation O¹_(NORMAL) of O¹(45°, −45°)_(NORMAL).

Images captured by the imaging capsule 110 may be associated with agiven time so that the image orientation (i.e., the orientation of theimage axis 145) may be determined at a number of discrete times. Forexample, I¹ (image 1) may be associated with Z¹ _(CAP) and Z¹ _(BODY)and a determination of O¹ _(NORMAL) would therefore be an indication ofthe normalized orientation of I¹ relative to the body of the subject 100and the body coordinate system 600 frame of reference (FIGS. 6 and 11)at T₁. Additionally, I¹ (image 1) may be associated with R¹ _(CAP) andR¹ _(BODY) and a determination R¹ _(NORMAL) may be the normalizedrotation of I¹ relative to the body of the subject 100 and the bodycoordinate system 600 frame of reference.

Images and corresponding data may be captured at various suitableintervals. For example, images and corresponding data may be capturedevery second, tenth of a second, or five images every tenth of a second,with one second between a set of such five images.

From the foregoing it will be appreciated that, although specificembodiments have been described herein for purposes of illustration,various modifications may be made without deviating from the spirit andscope of the disclosure. Furthermore, where an alternative is disclosedfor a particular embodiment, this alternative may also apply to otherembodiments even if not specifically stated.

1. An apparatus comprising: an image capture device having an imageaxis; and a gyroscope operable to indicate the orientation of the imageaxis.
 2. The apparatus of claim 1, further comprising: a housing; andwherein the image capture device and gyroscope are disposed within thehousing.
 3. The apparatus of claim 2, wherein the housing is ingestible.4. The apparatus of claim 2, wherein the housing is operable to beingested and to pass through the gastrointestinal tract of a subject. 5.The apparatus of claim 4, wherein the image capture device is operableto capture an image within the gastrointestinal tract.
 6. The apparatusof claim 2, wherein at least a portion of the housing is transparent. 7.The apparatus of claim 1, further comprising a wireless module operableto send an indication of the orientation of the image axis.
 8. Theapparatus of claim 7, wherein the wireless module is operable to sendthe indication of the orientation of the image axis to an external unit.9. The apparatus of claim 2, further comprising a light source disposedwithin the housing.
 10. The apparatus of claim 9, wherein the lightsource is operable to illuminate during image capture.
 11. The apparatusof claim 1, wherein the image capture device comprises a pixel array anda lens assembly.
 12. The apparatus of claim 1, wherein the gyroscope andimage capture device are disposed on a single integrated circuit die.13. The apparatus of claim 1, further comprising a power supply.
 14. Anapparatus comprising: a gyroscope operable to indicate an orientation ofa subject; and a harness wearable by a subject and operable to maintainan alignment of the gyroscope with the subject.
 15. The apparatus ofclaim 14, further comprising a wireless module operable to receive anindication of the orientation of an image axis.
 16. The apparatus ofclaim 15, wherein the wireless module is operable to receive theindication of the orientation of the image axis from an imagingapparatus located within the gastrointestinal tract of a human subject.17. The apparatus of claim 14, wherein the gyroscope and wireless moduleare disposed on a single integrated circuit die.
 18. The apparatus ofclaim 15, further comprising a processor operable to compare anindicated orientation of the subject and an indicated orientation of theimage axis.
 19. The apparatus of claim 15, wherein the processor isfurther operable to determine the orientation of the image axis relativeto the frame of reference of the wearer.
 20. A system comprising: afirst apparatus comprising: a housing; an image capture device disposedwithin the housing and having an image axis; and a first gyroscopedisposed within the housing and operable to indicate the orientation ofthe image axis; and a second apparatus comprising: a gyroscope operableto indicate an orientation of a subject; and a harness wearable by asubject and operable to align the gyroscope with the subject.
 21. Thesystem of claim 20, wherein the housing is ingestible.
 22. The system ofclaim 20, wherein the housing is operable to be ingested and to passthrough the gastrointestinal tract of a subject.
 23. The system of claim22, wherein the image capture device is operable to capture an imagewithin the gastrointestinal tract.
 24. The system of claim 20, whereinat least a portion of the housing is transparent.
 25. The system ofclaim 20, wherein the first apparatus comprising a wireless moduledisposed within the housing and operable to send an indication of theorientation of the image axis to the second apparatus.
 26. The system ofclaim 20, wherein the first apparatus further comprises a light sourcedisposed within the housing.
 27. The system of claim 26, wherein thelight source is operable to illuminate during image capture.
 28. Thesystem of claim 20, wherein the image capture device comprises a pixelarray and a lens assembly.
 29. The system of claim 20, wherein the firstgyroscope and image capture device are disposed on a single integratedcircuit die.
 30. The system of claim 20, wherein the first apparatusfurther comprises a power supply.
 31. The system of claim 20, whereinthe second apparatus further comprises a wireless module operable toreceive an indication of the orientation of an image axis.
 32. Thesystem of claim 31, wherein the second gyroscope and wireless module aredisposed on a single integrated circuit die.
 33. The system of claim 20,further comprising a processor operable to compare an indicatedorientation of the subject and an indicated orientation of the imageaxis.
 34. The system of claim 33, wherein the processor is furtheroperable to determine the orientation of the image axis relative to theframe of reference of the subject.
 35. The system of claim 20 furthercomprising a memory operable to store a plurality of image axisindications, a plurality of subject orientation indications, and aplurality of images.
 36. A method comprising: determining theorientation of a body axis relative to a first frame of reference;determining the orientation of an image axis relative to the first frameof reference; and determining the orientation of the image axis relativeto the body axis.
 37. The method of claim 36, comprising determining theorientation of a body axis relative to a first frame of reference via agyroscope.
 38. The method of claim 36, comprising determining theorientation of an image axis relative to the first frame of referencevia a gyroscope.
 39. The method of claim 36, comprising subtracting thedetermined orientation of the body axis from the determined orientationof the image axis.
 40. The method of claim 36, comprising associatingthe determined body axis orientation and image axis orientation with animage.
 41. An apparatus comprising: a gyroscope operable to indicate theframe of reference of a wearer; and a wireless module operable toreceive an indication of the orientation of an image axis relative to aframe of reference.
 42. The apparatus of claim 41, wherein the gyroscopeand wireless module are disposed on a single integrated circuit die.